Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add diegosouzapw/awesome-omni-skills --skill agent-tool-buildergit clone --depth 1 https://github.com/diegosouzapw/awesome-omni-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/diegosouzapw/awesome-omni-skills/agent-tool-builder)<a href="https://agentmods.dev/skills/diegosouzapw/awesome-omni-skills/agent-tool-builder"><img src="https://agentmods.dev/badge/skills/diegosouzapw/awesome-omni-skills/agent-tool-builder/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/diegosouzapw/awesome-omni-skills/agent-tool-builder"><img src="https://agentmods.dev/badge/skills/diegosouzapw/awesome-omni-skills/agent-tool-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00051 | $0.05929 |
| Opus 5 | $0.00026 | $0.02965 |
| Sonnet 5 | $0.00010 | $0.01186 |
| Haiku 4.5 | $0.00005 | $0.00593 |
Grade A, and why
agent-tool-builder scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
data = weather_api.fetch(location) This is a copy
91% identical to agent-tool-builder-v2 — 18 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 816 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Tool Builder
Overview
This public intake copy packages plugins/antigravity-awesome-skills-claude/skills/agent-tool-builder from https://github.com/sickn33/antigravity-awesome-skills into the native Omni Skills editorial shape without hiding its origin.
Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.
This intake keeps the copied upstream files intact and uses the external_source block in metadata.json plus ORIGIN.md as the provenance anchor for review.
Agent Tool Builder Tools are how AI agents interact with the world. A well-designed tool is the difference between an agent that works and one that hallucinates, fails silently, or costs 10x more tokens than necessary. This skill covers tool design from schema to error handling. JSON Schema best practices, description writing that actually helps the LLM, validation, and the emerging MCP standard that's becoming the lingua franca for AI tools. Key insight: Tool descriptions are more important than tool implementations. The LLM never sees your code - it only sees the schema and description.
Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Capabilities, Scope, Tooling, Patterns, 1. Detailed Descriptions (Most Important), 2. Parameter Descriptions.
When to Use This Skill
Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.
- User mentions or implies: agent tool
- User mentions or implies: function calling
- User mentions or implies: tool schema
- User mentions or implies: tool design
- User mentions or implies: mcp server
- User mentions or implies: mcp tool
Operating Table
| Situation | Start here | Why it matters |
|---|---|---|
| First-time use | metadata.json |
Confirms repository, branch, commit, and imported path through the external_source block before touching the copied workflow |
| Provenance review | ORIGIN.md |
Gives reviewers a plain-language audit trail for the imported source |
| Workflow execution | SKILL.md |
Starts with the smallest copied file that materially changes execution |
| Supporting context | SKILL.md |
Adds the next most relevant copied source file without loading the entire package |
| Handoff decision | ## Related Skills |
Helps the operator switch to a stronger native skill when the task drifts |
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 11d ago First seen · 816 lines · 51 tokens per session scan A cb9d00ab38c1
agent-tool-builder is a skill published in the GitHub repository diegosouzapw/awesome-omni-skills (140 stars, last pushed 2mo ago), licensed MIT. It adds 51 tokens to every session and 5,929 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 91% identical to agent-tool-builder-v2, differing in 18 lines, and is treated as a copy.
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